Reverse blast oil burner



April 1932- w. E. JOHNTON 1,853,277

REVERSE BLAST OIL BURNER Filed Nov. '7, 1927 2 Sheets-Sheet 1 April 12, 1932-- w. E. JOHNSTON 1,853,277

REVERSE BLAST OIL BURNER Filed Nov. 7, 1927 2 Sheets-Sheet 2 13 other structures.

Patented Apr. 12, 1932 Utllli li n stars WAYIBURN' E.- JOHNSTON, OF MTINNEAPOLIS,v MINNESOTA REVERSE BLAST OIL BURNER i Application filed November 7, 1927. Serial No. 231,566;

This invention relates to an oil burner of the type using air under pressure. Such burners are now used for heat treating and forging furnaces, as well as steam boilers and In all of these applications, the'burner, so called, in operation delivers a mixture of air and atomized oil into a combustion chamber. It has been the aim of designers and inventors of such burners,

19 to provide a structure which would effectively'atomize the oil and mix the air therewith. In such burners, it is necessary to arrange for a considerable variation in the out-put. It is essential that this variation of the output should be accomplished without varying the uniform mixture of oil and air. It is also desirable, in such a burner, to maintain the full air pressure at the portion of the burner in which the oil is atomized, in order that the atomization may be as efiicient as possible at the low output of said burner, as at the high output thereof. In the burners of the prior art, the atomizing air has generally been delivered more or lessin the sameaxial direction as the oil. It is an object-of this invention, therefore, to provide anoil burner using air under pressure, in which the stream of air, just before it leaves the burner, has the atomized oil distributed uniformly there- 7 through, within the burner itself. g

It is another object of the invention to provide anoil burner using air under pressure in which the air is directed into the oil stream in a direction different from that of the oil stream, for atomizing the oil. a 7

It is a further object of the invention to provide an oil burner in which the full air pressure is maintained at the portion thereof where the oil is atomized.

It is still another object of the invention to provide an oil burner in which the main air valve is opened wide at all times and control of the air delivery is had by means of a secondary air regulator which surrounds the primary'atomizing jet.

It is still another object of the invention to provide an'oil burnerhaving an oil passage and a discharge head from which the oil passes, together with means for directing air toward said oil in a directionreverse to that of said oil, together with a passage through which the mixed oil and air areprojected with a rolling motion.

It is still another object of the invention to provide an oil burner having an oil passage and a discharge head at the end thereof, with means'f'or directing air into the oil stream in circumferentially spaced. directions directed radially toward said oil stream, the burner having ,a passage through whichthe mixed oil and air are projected, and having means for'directing secondary air into said mixed oil and air from various circumferential clirections directed toward the axis .of the streamof mixed oil and air.

It is also an object of the invention to pro vide an oil burner such as set forth in the preceding paragraph, in'whi'ch the last mentioned means is adjustable to vary the amount of the air. a These and other objects and advantages of the invention will'b'e fullysetforth in the following description made in. connection with the accompanying drawings,-in which like reference characters refer to similar parts throughout'the several views and in which r r Fig. 1 is a view mostly in vertical section taken on line 11-0f Fig. 2, a portion thereof being shown'in side elevation;

Fig. 2. is a top plan View of the -burner;

Fig. 3 is a view in reareleva'tion of the burner; 1 1 r Fig. 4 is a vertical section taken on line- 4-4 of Fig. 1, as indicated by the arrows; and

F ig. 5 is a vertical section taken on line" 5'5 of Fig. 1 as indicatedby the arrows.

Referring to the drawings, a burner is shown, comprising the casing 10. This cas-' ing l0has a substantially cylindrical upper portion 10a having a flange 10?) extending thereabout, on which rests and'to which is secured by the screws, 12, an auxiliary casing 11. The casing 11 extends to one side of casing 10 as shown in Figs. 2 and 3, and has move able therein a plate valve 13 which rests on the top of casinglO and which has an upwardly extending central stem 13a received in a boss. on the end of arm 14, the coil spring 15 being disposed between valve 13 and arm 14, bear-{ 1 ing against the same respectively at its ends and surrounding the hub at the end of arm 14. The arm 14 has a hub at its other end secured to a spindle 16 having a reduced lower end extending through arm 14 and into a lug 100 on the flange 10?), said stud having an enlarged and threaded. upper end threaded into a boss 11a on casing 11 and on which is placed a jamb nut 17. The handle lever 18 is secured to the upper end of stud. 16 forthe purpose of swinging arm 14 and valve 13. The casing 10 has a discharge opening 100 surrounded by a flange or nozzle 10 said opening flaring toward the edge of said flange. The portion of member 10 about the inner end of opening 10c is-frusto-conical and extends in a reversecurve, thus forming an annular trough portion 102'. Said nozzle is surrounded by a flange 10g having holes therein adapted to receive the headed and nutted bolts 19 by which the/burner is attached to the wall 20 of thie furnaceor other structure to which it is applied. The casinglO' has an opening 10h in its'rearwall, into which projects a membet-21', said member having a flange21a-engaging casing 10 about the opening 10h, and being secured thereto by'the circumferentiallyspaced'screws 22. The member 21 has ashell portion 21?), substantially the inner "half of which is cylindrical and the remainder of-which is semi-cylindrical, the said semi-cylindrical portion also having'th'e slots 210' th'erethrough. The cylindrical portion ofsaid shellhas formed or fitted'th erein a member 21d having an annular troughlike an outwardly flaring opening 216 extends w through member 21dand said cylindrical portion.- The member 21 hasa central stem 21; from which extends downwardly at the rear of said member a lug 21g, said members. 2'1fand 21g hav'ing extending therethrough an oil'passage 21h. The stem 21fterminates in or has secured to its front end, a fla'ringor frusto conicalhead 21i having a frusto-conical surface in its front :end, said memberhavj ing'asmall frusto-conical portion immediatelymirrounding the end of passage 21h'so that a concave annular shallow trough'is formed about the'end of. passage 217a. An oil supply pipe- =23is connected to theportion 21g and will extend tothe oil supply. The member 21 has astem 21y projecting 'rearwardly from portion=21g on which is rotatably mounted a cam'le'ver' 24. This lever has a helical cam surface'24iz at its rearward'end, engaging withthe'side of a screw 25 which is secured in stem 2147'. Member 24 has a groove 24?) formed between flanges thereon, in which groove is seated a plate 26. The plate 26 has extending therethrough a plurality of rods 27 held therein by the nuts 28 at each side of said plate, which rods pass through member 21d and are threaded into an adjustable member 29 having a central opening surrounding the cylindrical projection on member 21b. Springs 30 surround the rods 27 respectively and abut against flange 21a at one end and against one of the nuts 28 at the other end, thus tending to move rods 27 outwardly or backwardly. The member 29 has an outwardly flaring or conical surface in its front side and the edge portion thereof adjacent its central opening is also frusto-conical, so that a concave shallow trough is formed in said member. It will be noted that the frusto-conical surface on the inner end of the central portion of member 2145 is reversely disposed in respect to the flaring portion of head 212', and that the annular troughs in said members respectively face each other. It will also be noted that the annular troughs formed in member 29 and in the inner portion of member 10 surrounding the opening 104;, face each other. Annular narrow passages are thus formed between members 210 and 21d and between member 29 and trough por-- tions 10i of casing. 10, as indicated by the arrows in Fig. 1.

In operation the lever 18 is moved sothat the top of casing 10a! is substantially entirely uncovered by plate 13. Air under pressure is supplied through casing 11. Thisair passes down in casing 10 into the open front end of member 21d at the upper portion thereof and through'the slots 210 at the lower portion thereof, as indicated by the arrows in Fig. 1. Oil-is supplied through pipe 23 and passes through passage 21h and is discharged at the end of said passage through head 2111. The air returns through the narrow annular passage as indicated by thereversely curved arrows in Fig. 1, and as'clearly indicated by said arrows, this air is moving inwardly or rearwardly in .a direction substantially reverse to or at an obtuse angle to the direction of the oil stream, that is, the air is moving toward the rear of the burner in said 1 passage, while the oil is being discharged forwardly or outwardly of the burner. The air thus rushing through the passage between surface 2111 and the adjacent surface of member 2111! toward the oil stream from all circumferential directions, actsvery effectively to atomize the oil and the atomized mixture is discharged outwardly through the passage 21c. It will be noted that the general direction of the annular passage between the frusto-conical head 212' and the adjacent surface on member 210! makes an obtuse angle with the axis of the horizontal portion of oil passage 21h. The mixture is given a rolling action through said passage, as indicated by the arrows in Fig. 1. This mixture passes outwardly from passage 21c and is again met by the secondary air passing between the front end of member 29 and the conical portion of casing 10. This secondary air as shown by the arrows in Fig. 1, is also directed inwardly toward the axis of the stream of mixed oil and air from all circumferential directions. This air is thus also effectively mixed with the mixture of oil and air and thus also passes outwardly through the passage 106 in a cloud of very finely atomized oil and air, which mixture also has a rolling motion as it passes through passage 10a. The air and oil are thus completely mixed within the burner and a very efficient combustible mixture is formed in the burner and is discharged therefrom into the combustion chamber of the furnace. The member 29 can be moved forward and rearwardly by movement of the lever 24: and this lever will remain in the position to which it is moved. The regulation of the burner is thus effected by regulating the secondary air and there is always a full air pressure on the burner whether it is running at low output or high output. The burner is thus operated at all times with the main air valve opened wide and as stated, the full air pressure is always on the burner substantially at the point where the oil and air meet or where the oil is atomized. The air rushing through the annular passage from all circumferential directions toward the surface adjacent the outlet for the oil causes a high pressure to be maintained at the point of the oil discharge and a great turbulence of air is produced at the point of oil discharge. The air converging at this point must pass outwardly through the flaring passage in member 21 and the mixed oil and air passes out through the flaring passage with the greatest outward velocity adjacent the axis of this passage. Tests on the burner have shown that there is an inward movement of air along the wall of the flaring passage. The outward motion adjacent the axis of the passage and this inward movement adjacent the wall of the passage gives the rolling effect as indicated in Fig. 1. This is somewhat similar to the well known smoke ring formation sometimes caused in locomotive stacks. While the air is directed in the annular passage adjacent head 21 and the oil outlet toward the surface surrounding the oil outlet, some of theair no doubt reaches the oil without engaging the surface adjacent the oil outlet. The air is, of course, deflected into the general direction of the oil stream. The oil stream, however, expands after leaving the oil outlet and the flow of air is not smooth oruniform, but irregular. There is a violent agitation of the air and oil and this, together with the rolling action described, breaks up the oil so that a very effective atomization of the oil is secured. It will be seen that the member 21 can be removed by removing the screws 22 and this carries with it also the, member 29 and rods 27.

It is also noted that thereis 'a slight space between member 29 and the cylindrical projection of the member 21d surrounded thereby. This is provided so that air will pass through the small passage. Any oil which might collect on the edge of the central open ing in member 29, particularly at the upper portionthereof, willbe carried awayby said air and the oil will thus not collect in drops and run onto the projection on member21d.

From the above description it is seen that applicant has provided a very simple and efiicient oil burner. The atomization of the oil and the mixing thereof with the air. is

highly effi'cient. The oil and air are mixedin an exceedingly fine mist within the burner and dischargedinto the combustion chamber.

in a very effective condition to be burned. The fire supplied with the combustible mixture from the burner is a glowing mass of uniform appearance indicating a very finedivision of oil and averyintimate mixture therewith of air. The regulation of the burner is very easily effected; The burner is very simple in construction "and comprises very'few parts. The same has been amply demonstrated in actual practice and found to be very successful and efficient and is being commercially made.

It will, of course,.be understood that various changes may be made in the form, de-

tails, arrangements and proportions of the parts, .without departing from the scope of applicants invention, which, generally stated, consists in. a device capable of carrying out the objects above set forth, in the novel parts and combinations of parts disclosed yond the bottom of said trough, a member spaced from said surface and having a forwardly flaring passage for oil and air there through axially 'alined with said oil passage.

annular passage toward the oil discharge in all circumferential directions, and the mixed oil and air are directed outwardly through ing aisurface extending outwardly and forwardly, and a fourth member spaced from sajdllast mentioned surface and having a forwardly flaring, passage therethrough of greater diameter than and axially alined with said. first mentioned passage, said first and second mentioned members having an annuluconicalair-rpassage formed therebetween and said third and fourth members having an annular: air passage formed therebetween and an air chamber containing air under pressureawith which said passages communicate,:whereby air'is directed through said passages. toward theaxis of said passages, and the? mixed oil and air passes outwardly through said flaring passages.

3. The structure set forth in claim 2, said third member and fourth member being relativelymovable to vary the size of the air passage therebetween.

4.- An; oil burner using low pressure air having-in combination, a member having an oil discharge passage therethrough and an oil outletsurrounded by an annular troughlike-surface, a member spaced from said first member and'outlet and having a forwardly flaring passage axially alined with said oil passage and outlet'the inlet thereto being forwardly spaced'from said outlet, and means fom'directing air between said members substimtial-ly toward said oil outlet for engaging said; oil andvcausing the mixed oil and air to pass outwardly through said flaring passagmwhereby there is a strong outward current=adjacent the axis of said flaring passage andpaninwardly directed air current adjacent the wallof said passage, giving a rollingaction to the mixed air and oil.

In testiinonywhereof I afiix my signature.

VVAYBURN E. JOHNSTON. 

